JP6413012B2 - Elevating step of work vehicle - Google Patents

Description

  The present invention relates to an elevating step of a work vehicle.

2. Description of the Related Art Conventionally, in a work vehicle such as a wheel loader, it has been known that an operator is provided with an ascending / descending step for moving between the ground and an engine room (see, for example, Patent Document 1). Such an elevating step is suspended downward from the vehicle main body further behind the rear wheel.
However, in the lifting and lowering step of the wheel loader, the portion that hangs down beyond the back-spacing angle regulation line connecting the grounding part of the rear wheel and the lower surface of the counterweight at the rear of the vehicle is during the scooping work for excavating while climbing the ground. When the front side of the vehicle body is inclined upward, it may be damaged by contact with the ground.

Therefore, in the elevating step described in Patent Document 1, the upper tread is composed of a fixed tread that is disposed on the front side of the vehicle, and a rotating tread on the rear side of the vehicle that is rotatably coupled thereto. And the upper end of the elastically deformable first suspension member is rotatably connected to the front end of the fixed tread, the upper end of the second elastically deformable second suspension member is connected to the rear end of the rotation tread, A lower footboard is rotatably connected between the lower ends of the first and second suspension members.
According to such a configuration, when the lower step board comes into contact with the ground during the scraping operation, the lower step board receives an external force so as to be driven backward, but the lower step board is applied to the first and second suspension members. The first and second suspension members rotate with respect to the fixed tread plate and the rotating tread plate, and the rotating tread plate rotates upward with respect to the fixed tread plate. It is said that it can be folded and escaped between the fixed part to the ground and the ground, that is, above the back-spacing angle regulation line that is at the same level as the ground, and damage to the footboard etc. can be prevented.

On the other hand, Patent Document 2 describes a large hydraulic excavator having a ladder in front of the vehicle. And then. In Patent Document 2, it is proposed to further provide an elevating step at the lower end of such a ladder. This elevating step is for the operator to move up and down from the front of the vehicle, and two parallel links are vertically suspended on the side plate on one side of the ladder in the vehicle width direction, Two parallel links are also provided on the side plate on the side so as to be rotatable in the vehicle longitudinal direction, and a tread plate is provided between the parallel links spaced apart in the vehicle width direction to form a four-bar link.
Even in such an elevating step, when the ground sinks due to the weight of the vehicle in soft ground and the lower end of the elevating step contacts the ground, the tread plate rotates with respect to the lower end of the parallel link, and the parallel link becomes the side plate of the ladder. Therefore, the tread board escapes upward, and the tread board and the like can be prevented from being damaged. Moreover, since such a raising / lowering step is added to the lower end of a ladder and a tread is in the position close | similar to the ground, there also exists an advantage that the access between the ground and a ladder can be made easy via a raising / lowering step.

JP 2013-2209 A JP 2008-240278 A

By the way, in recent years, it has been required to further lower the height from the ground to the lowest tread of the lifting step to further facilitate access.
However, in the conventional lifting step described in Patent Document 1, since the first and second suspension members themselves are elastically deformed freely, the lengths of such first and second suspension members are simply increased, If only the treadle is increased as needed, the first and second suspension members will be deformed by twisting etc. when the treadle is stepped on during lifting, and the lifting step will be greatly swung back as viewed from the lifting operator. It is not stable and it is difficult to move up and down.

  Moreover, in the conventional raising / lowering step of patent document 2, since the link connected with the both ends of the tread board is metal, about the stability of the raising / lowering step at the time of raising / lowering, the lift step of patent document 1 is large. Although it is thought that it does not decrease, the frequency with which the treads collide with rocks on the ground increases as much as the tread is closer to the ground, so the link may be significantly deformed, resulting in a problem with durability. In particular, such a problem becomes conspicuous when the link comes into contact with the ground during work, such as a wheel loader.

  An object of the present invention is to provide an elevating step for a work vehicle that is easy to move up and down and has excellent durability even when the height from the ground is lowered.

  As for the raising / lowering step of the work vehicle vehicle of the present invention, one step is formed by a tread plate and a front side connecting member and a rear side connecting member whose lower ends are rotatably connected to both ends of the tread plate in the longitudinal direction of the vehicle, The step is an ascending / descending step of the work vehicle provided with a plurality of steps, and the upper end of the front connection member and the rear connection member of the step located at the uppermost part are rotatably connected to the side position of the vehicle body, In addition, the upper ends of the front connection member and the rear connection member of the step positioned below the uppermost step are arranged in parallel in the vehicle front-rear direction and the vehicle front and rear of the step plate positioned immediately above Among the steps located above the lowest step, at least the front connection member and the rear connection member of the step located at the top are rigid members. Located at the top Of the stage located in the lower portion than the stage, front connecting member and the rear connecting member of stages positioned on at least the bottom is characterized in that is provided to be elastically deformable.

  The lifting / lowering step of the work vehicle according to the present invention includes a first front connection member and a first rear side, the upper end of which is rotatably connected to a side position of the vehicle body and arranged in parallel at a predetermined interval in the vehicle front-rear direction. A connecting member, a first tread plate rotatably connected between the lower ends of the first front connecting member and the first rear connecting member, and an upper end of the first tread plate so as to be rotatable at both ends in the vehicle front-rear direction. A two-stage including a connected second front connecting member and second rear connecting member, and a second tread plate rotatably connected between lower ends of the second front connecting member and the second rear connecting member. The first front connection member and the first rear connection member are rigid members, and the second front connection member and the second rear connection member are provided to be elastically deformable. .

  The lifting / lowering step of the work vehicle according to the present invention includes a first front connection member and a first rear side, the upper end of which is rotatably connected to a side position of the vehicle body and arranged in parallel at a predetermined interval in the vehicle front-rear direction. A connecting member, a first tread plate rotatably connected between lower ends of the first front connecting member and the first rear connecting member, and an upper end rotatably connected to both ends of the first tread plate in the vehicle front-rear direction. The second front connecting member and the second rear connecting member, the second tread plate rotatably connected between the lower ends of the second front connecting member and the second rear connecting member, and the upper end of the second front connecting member and the second rear connecting member. A third front connection member and a third rear connection member rotatably connected to both ends of the tread board in the vehicle front-rear direction and a lower end of the third front connection member and the third rear connection member are rotatable. A third tread plate connected to the first front connection member and the first rear connection member. Second front connecting member, and a second rear connecting member is a rigid member, the third front connecting member and the third rear connecting member and being provided to be elastically deformable.

  The “rigid member” means a member made of a material or the like for preventing positive elastic deformation, and elastic deformation on physical properties of the member used in such a configuration is allowed. On the other hand, “elastically deformable” means positively elastically deformable.

  According to the present invention, since the front side connecting member and the rear side connecting member that are at the uppermost part of the lifting step and are connected to the vehicle body are rigid members, the length of the hanging portion of the lifting step is increased, Even when the height is lowered, it is possible to suppress the deflection to the back side when entering the lowest tread, and to easily move up and down. In addition, since the lowermost front side connecting member and rear side connecting member are provided so as to be elastically deformable, the frequency of contact with the ground increases as the length of the suspended portion is increased to reduce the height from the ground. Even if this happens, the durability can be improved without being easily damaged.

In the lifting / lowering step of the work vehicle according to the present invention, the elastically deformable front side connecting member and rear side connecting member are preferably configured to include a laminate of a plurality of elastic plates.
In the elevating step of the work vehicle according to the present invention, the upper and lower ends of all the front connection members and the rear connection members are the connection brackets fixed to the vehicle body or the connection brackets provided at both ends in the vehicle front-rear direction. The connection bracket is provided with a notch opening that opens toward at least one of the upper and lower sides and accommodates the front connection member and the rear connection member that rotate. It is preferable.
In the lifting / lowering step of the work vehicle according to the present invention, a back angle defining line connecting a wheel provided on the vehicle main body and a vehicle rear lower portion of the vehicle main body, and a front connection member and a rear connection member connected to the vehicle main body. It is preferably folded between the connecting position to the vehicle body.

The perspective view of the work vehicle by which the raising / lowering step which concerns on 1st Embodiment of this invention was employ | adopted. The perspective view of an raising / lowering step. The side view which shows the raising / lowering step at the time of the scraping work by a working vehicle. The perspective view of the raising / lowering step which concerns on 2nd Embodiment of this invention.

<First Embodiment>
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a wheel loader 1 as a work vehicle in which an elevating step 10 according to this embodiment is employed. FIG. 2 is a perspective view of the lifting step 10.

[Wheel loader overview]
1 and 2, the wheel loader 1 includes a vehicle main body 2, a work machine 3, a cab 4, a traveling device 5, and a power unit 6.
The vehicle main body 2 is composed of a steel frame body that supports the work machine 3, the cab 4, and the power unit 6. A structure 21 is provided on the front side of the vehicle body 2 so as to be rotatable in the left-right direction with respect to the vehicle body 2, and a work implement 3 is provided further on the front side of the structure 21.

The work implement 3 includes a boom 31 pivoted on the structure body 21, a bucket 32 pivoted up and down on the boom 31, and a bell crank 33 pivoted on the boom 31 at an intermediate portion of the boom 31.
A pair of booms 31 are arranged in the vehicle width direction, and pivotally pivoted up and down with respect to the structure 21. A lift cylinder (not shown) is pivoted at an intermediate portion of the boom 31, and a base end portion of the lift cylinder is pivoted by the structure 21. The boom 31 is rotated up and down by expanding and contracting the lift cylinder by hydraulic pressure.

The bucket 32 is a portion for loading excavated soil and the like. In the bucket 32, a link (not shown) is pivoted above the pivot position with respect to the boom 31, and the other end side of the link is pivoted on the lower end portion of the bell crank 33.
The bell crank 33 is pivoted between the pair of booms 31 and the lower end is connected to the base end portion of the link. A tilt cylinder 34 is pivoted on the upper end of the bell crank 33, and a base end portion of the tilt cylinder 34 is pivoted on the structure 21.

  Then, when the bucket 32 moves forward in a state where the bucket 32 is positioned near the ground position and the lift cylinder is extended while the bucket 32 enters the excavation target such as earth and sand, the boom 31 is loaded with the excavated soil in the bucket 32. Can rotate upward to perform excavation work. Further, when the tilt cylinder 34 is contracted with the bucket 32 positioned upward, the upper end portion of the bell crank 33 rotates toward the vehicle body 2 and the lower end portion of the bell crank 33 rotates toward the vehicle front side. Then, the upper part of the bucket 32 is pushed to the front side of the vehicle by the link, whereby the bucket 32 is rotated, and the excavated soil loaded in the bucket 32 can be lowered onto a loading platform such as a dump truck.

  The traveling device 5 includes a front wheel 5A and a rear wheel 5B as wheels provided at four locations on the side surface of the vehicle main body 2, and the front and rear wheels 5A and 5B are not shown in FIGS. An axle that is rotatably supported on the axle and a drive shaft that is connected to the axle at a substantially central portion in the vehicle width direction of the vehicle body 2 via a differential are provided. The drive shaft is connected to an engine installed in the power unit 6 via a torque converter. When the engine rotates, the rotational speed is converted by the transmission via the torque converter, the drive shaft rotates, and the differential and axle Is transmitted to the front and rear wheels 5A, 5B, and the wheel loader 1 travels.

  Here, an operator or a maintenance man goes back and forth between the rear wheel 5B and the rear end 2A as the end of the vehicle main body 2 at the lateral position of the vehicle main body 2 to move between the ground and the engine room. 10 is provided. In recent years, it has been desired that the height from the ground GL should be lowered (in this embodiment, 600 mm is assumed) in order to make access easier in such an elevating step 10. The length is longer than before. As a result, the lower end side of the raising / lowering step 10 hangs down significantly beyond the back angle defining line DL as compared with the conventional case. The back separation angle defining line DL is a line connecting the rear wheel 5B and the counterweight lower surface 2B as the vehicle rear lower portion of the vehicle body 2, and is a line defining the back separation angle θ.

  As one of the operations by the wheel loader 1, there is a scraping operation. This work is an operation of climbing while excavating a natural mountain in front of the vehicle with the bucket 32. As the natural mountain is climbed, the entire vehicle body 2 is inclined so that its front is upward. The maximum tiltable range is determined by the back separation angle θ. For this reason, at the time of such a scraping operation, the vehicle main body 2 may be tilted to the last minute, and the portion that hangs down beyond the back separation angle defining line DL of the elevating step 10 is in contact with the ground GL. For this reason, a folding structure that folds and escapes upon contact with the ground GL is generally employed as the lifting step, and the length of the hanging portion is longer while adopting the folding structure also in the lifting step 10 of the present embodiment. It solves the problem that occurs when Hereinafter, the lifting step 10 will be described in detail.

[Description of the entire lifting step]
FIG. 2 is a perspective view of the lifting step 10. FIG. 3 is a side view showing a state of the raising / lowering step 10 during the scraping work by the wheel loader 1.

  2 and 3, the elevating step 10 includes a first front side connecting member 11 having an upper end rotatably connected to a side position of the vehicle body 2 and arranged in parallel at a predetermined interval in the vehicle front-rear direction. The first rear connection member 12, the first tread plate 13 rotatably connected between the lower ends of the first front connection member 11 and the first rear connection member 12, and the vehicle front-rear direction of which the upper end is the first tread plate 13. The second front connection member 14 and the second rear connection member 15 that are rotatably connected to both ends of the first connection member 15 and the lower ends of the second front connection member 14 and the second rear connection member 15 are rotatably connected. The second tread plate 16 is provided in a two-stage configuration. The first front connection member 11 and the first rear connection member 12 are rigid members made of a metal material or the like, and the second front connection member 14 and the second rear connection member 15 are formed to include an elastic material and are elastic. It is provided so as to be deformable.

  That is, in the elevating step 10, one step is formed by the first tread plate 13 and the first front connection member 11 and the first rear connection member 12 whose lower ends are rotatably connected to the first tread plate 13. One step is formed by the second tread plate 16 and the second front connecting member 14 and the second rear connecting member 15 whose lower ends are rotatably connected to the second tread plate 16. 13 and the second tread 16) are provided in a two-stage configuration with two stages. And the upper end of the 2nd front side connection member 14 and the 2nd back side connection member 15 is connected with the both ends of the 1st tread 13 of the step immediately above.

[Explanation of folding structure of lifting step]
More specifically, a box-like body 2C such as a battery box or a tool box is provided on the side of the vehicle main body 2, and a pair of metal parts is provided on the side surface of the box-like body 2C with a bolt in the longitudinal direction of the vehicle. These connection brackets 17 are fixed, and the upper ends of the first front connection member 11 and the first rear connection member 12 are rotatably attached to these connection brackets 17. The upper ends of the first front connection member 11 and the first rear connection member 12 are cylindrical portions 11A and 12A, and the cylindrical portions 11A and 12A are interposed between a pair of attachment pieces 17A provided on the connection bracket 17. The horizontal bolts 17E penetrating the cylindrical portions 11A, 12A and the attachment pieces 17A in the vehicle width direction are rotated about a rotation axis. In the present embodiment, the front and rear connecting brackets 17 are joined by three steel plate members 18A, and the uppermost tread plate 18 is formed by these plate materials 18A.

The lower ends of the first front connection member 11 and the first rear connection member 12, and the upper ends of the second front connection member 14 and the second rear connection member 15 are also cylindrical portions 11B, 12B, 14A, 15A. Between the pair of attachment pieces 19A of the connecting bracket 19 provided at both ends in the vehicle front-rear direction.
The first tread 13 is formed of three steel plate members 13A joined between the front and rear connecting brackets 19.
Similarly, the lower ends of the second front connection member 14 and the second rear connection member 15 are also cylindrical portions 14B and 15B, and between the pair of attachment pieces 22A of the connection bracket 22 provided at both ends of the second tread plate 16 in the vehicle front-rear direction. The bolt 22E is pivotally attached to the pivot shaft.
The second tread plate 16 is also formed by three plate members 16A made of steel plates joined between the front and rear connecting brackets 22.
The connecting brackets 19 and 22 are also made of metal.
Thus, the folding structure of the raising / lowering step 10 is implement | achieved because the connection members 11, 12, 14, and 15 and the tread boards 13 and 16 rotate mutually.

[Description of elastic structure of connecting member]
At this time, the second front connection member 14 and the second rear connection member 15 are a block-like laminate 23 in which a plurality of elastic plates 23A formed of an elastic material such as synthetic rubber or natural rubber are integrated by riveting. And the metal hinge members 14C, 15C, in which the cylindrical portions 14A, 14B, 15A, 15B described above are formed at the upper and lower ends of the laminate 23, are fixed by a seat plate 24, bolts 25, and nuts 26. It is. The 2nd front side connection member 14 and the 2nd back side connection member 15 are provided with the elastically deformable laminated body 23, and have a structure which is hard to be damaged even if they contact the rock block etc. on the ground.

[Description of interference prevention structure of connecting bracket]
The connecting bracket 17 has a joining piece 17B to which the mounting piece 17A and the uppermost tread 18 are joined. In the front connecting bracket 17, a notch opening 17 </ b> C that opens downward in a U shape is provided at a position corresponding to between the attachment pieces 17 </ b> A of the joining piece 17 </ b> B. The upper ends of the rotated first front connection member 11 and first rear connection member 12 are accommodated in the notch opening 17C, and the first front connection member 11 and the first rear side when the elevating step 10 is folded. The side connecting member 12 and the connecting bracket 17 are prevented from interfering with each other. A restricting plate 17D that restricts the rear wheel 5B side, that is, forward rotation, is provided on the lower surface of the rear connecting bracket 17. The restriction plate 17D regulates the folding amount so that the lower end of the restriction plate 17D does not reach the rear wheel 5B when it is folded forward.

  Similarly, in the joint piece 19B of the connecting bracket 19, at a position corresponding to between the attachment pieces 19A, a cutout opening 19C opened upward in a U shape and a cutout opening 19D opened downward in a U shape. Is provided. The lower opening side of the rotated first front connection member 11 and the first rear connection member 12 is accommodated in the cutout opening 19C, and the second front connection member 14 and the second rear side rotated in the cutout opening 19D. The upper end side of the connecting member 15 is accommodated, and in addition to the interference between the first front connecting member 11 and the first rear connecting member 12 and the connecting bracket 19, the second front connecting member 14 and the second rear connecting member 15. And the connection bracket 19 are prevented from interfering with each other.

  And the joining piece 22B of the connection bracket 22 is also provided with a notch opening 22C opened upward in a U-shape at a position corresponding to between the attachment pieces 22A. The lower end side of the rotated second front side connecting member 14 and second rear side connecting member 15 is accommodated in the notch opening 22C, and the second front side connecting member 14, second rear side connecting member 15, the connecting bracket 22, and the like. To prevent interference.

[Explanation during scraping work]
When the lifting operation is performed by the wheel loader 1 adopting the lifting step 10 described above, as shown in FIG. 3, the wheel loader 1 reaches the position where the back separation angle defining line DL and the ground GL are at the maximum. It can be tilted so that the front of the main body 2 faces upward. In the middle of the inclination, when the lower end side of the lifting step 10 gradually approaches the ground GL and becomes a predetermined inclination or more, the second front side connecting member 14, the second rear side connecting member 15, and the second side on the lower end side. The tread 16 begins to rotate, then the first front connecting member 11, the first rear connecting member 12, and the first tread 13 rotate, and the entire lifting step 10 rotates to the rear side of the vehicle. It is folded between the angle defining line DL and the connection position to the vehicle body 2.
On the other hand, when excavation of the natural ground is completed and the wheel loader 1 moves backward, the back separation angle regulation line DL, that is, the counterweight lower surface 2B gradually moves away from the ground GL, so that the lifting step 10 is also gradually released from the folded state. And return to the original state.

[Effect of the embodiment]
According to the above embodiment, since the uppermost first front connecting member 11 and first rear connecting member 12 constituting the lifting step 10 are rigid members, the length of the hanging portion of the lifting step 10 is increased. However, even when the height from the ground is lowered, it is possible to suppress a swing or the like to the back side when stepping on the lowermost second tread plate 16, and to easily move up and down. In addition, since the lowermost second front side connecting member 14 and second rear side connecting member 15 are provided so as to be elastically deformable, the length of the hanging portion is increased and the height from the ground is reduced, so that the ground Even if the contact frequency increases, durability can be improved without being easily damaged.

Second Embodiment
FIG. 4 is a perspective view of an elevating step 10A according to the second embodiment of the present invention.
The elevating step 10A has a first front side connecting member 11 and a first rear side connecting member 12 whose upper ends are rotatably connected to a side position of the vehicle body 2 and arranged in parallel at a predetermined interval in the vehicle front-rear direction. And a first tread plate 13 rotatably connected between the lower ends of the first front side connecting member 11 and the first rear side connecting member 12, and an upper end of the first tread plate 13 so as to be rotatable at both ends in the vehicle front-rear direction. A second front side connecting member 14 and a second rear side connecting member 15 connected to each other; a second tread plate 16 rotatably connected between the lower ends of the second front side connecting member 14 and the second rear side connecting member 15; A third front side connecting member 27 and a third rear side connecting member 28 whose upper ends are rotatably connected to both ends of the second tread 16 in the longitudinal direction of the vehicle, and a third front side connecting member 27 and a third rear side connecting member 28. And a third tread plate 29 rotatably connected between the lower ends of the There is a stage configuration. In this embodiment, the 1st front side connection member 11, the 1st back side connection member 12, the 2nd front side connection member 14, and the 2nd back side connection member 15 are rigid members with a metal material etc., and the 3rd front side connection member 27 and the 3rd rear side connection member 28 are provided by the elastic material so that elastic deformation is possible.

  That is, in the elevating step 10A, one step is formed by the first tread plate 13 and the first front connection member 11 and the first rear connection member 12 whose lower ends are rotatably connected to the first tread plate 13, The second tread plate 16 and the second front connecting member 14 and the second rear connecting member 15 whose lower ends are rotatably connected to the second tread 16 form one step, and the third tread 29 and the lower end The third front side connecting member 27 and the third rear side connecting member 28, which are rotatably connected to the third tread plate 29, form one step, and as a whole, the tread plate (the first tread plate 13, the second tread plate 16, The third tread plate 29) has a three-stage configuration in which the third tread plate 29 is provided in three stages. The upper ends of the second front side connecting member 14 and the second rear side connecting member 15 are connected to both ends of the first step board 13 in the upper stage, and the upper ends of the third front side connecting member 27 and the third rear side connecting member 28. Are connected to both ends of the second tread 16 in the upper stage.

  Of these, the third tread plate 29 is also formed of three metal plate materials 29A as in the first embodiment. The third front side connecting member 27 and the third rear side connecting member 28 include a block-like laminate 23 in which a plurality of elastic plates 23A formed of an elastic material such as synthetic rubber or natural rubber are integrated by riveting, The laminated body 23 has a configuration in which the metal hinge members 27C and 28C in which the cylindrical portions 27A, 27B, 28A and 28B described above are formed at the upper and lower ends of the laminate 23 are fixed by the seat plate 24, the bolts 25, and the nuts 26. Other specific structures, such as the folding structure of the entire lifting step 10A, are the same as in the first embodiment. And about components, such as a connection bracket and a volt | bolt used similarly to 1st Embodiment, it shall suppose using the code | symbol in 1st Embodiment as it is, and it abbreviate | omits about the detailed description.

  Also in the present embodiment, since the uppermost first front connecting member 11 and the first rear connecting member 12 connected to the vehicle body 2 are rigid members, the lowermost third tread plate 29 is stepped on. Swinging to the back side can be suppressed, and lifting and lowering can be facilitated. In addition, since the lowermost third front side connecting member 27 and third rear side connecting member 28 are provided so as to be elastically deformable, the length of the suspended portion is lengthened and the height from the ground is reduced. Even if the contact frequency increases, durability can be improved without being easily damaged.

The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, although the form in which the uppermost tread 18 is provided has been described, such an uppermost tread 18 is not an essential component of the present invention, and is appropriately determined in consideration of the distance between the first tread 13 and the engine room. It can be omitted.

  The joint pieces 17B, 19B, and 22B of the connection brackets 17, 19, and 22 were provided with the notch openings 17C, 19C, 19D, and 22C. However, such as by changing the shape of the attachment piece or the joint piece. You may prevent interference with a connection member and a connection bracket, without providing a notch opening. However, if the size of the mounting piece, the shape of the joining piece, or the like is greatly changed, the strength of the entire connecting bracket may be affected. Therefore, it is preferable to provide a structure in which a notch opening is provided to avoid interference.

  The state in which the lifting step 10 is folded to the rear side of the vehicle body has been illustrated and described. However, the lifting step 10 naturally omits the restriction plate 17D when there is no fear of being caught in the rear wheel 5B, and the rear side of the vehicle body It is good also as a structure which folds also to the vehicle body front side in the state symmetrical with the state folded to the side.

  The elastically deformable connecting member may be provided so as to be elastically deformable using a single rubber plate, or elastically deformed by a composite member of a rubber plate and a flexible metal plate such as lead. It may be provided as possible.

  The raising / lowering step of the present invention may be configured in a two-stage configuration or a three-stage configuration, and may be configured in a plurality of stages including four or more stages. Among them, at least the front connection member and the rear connection member of the step located at the top of the steps located above the step located at the bottom are rigid members, and the step located at the top is higher than the step located at the top. Of the steps located in the lower part, at least the front connection member and the rear connection member of the step located in the lowermost part may be provided so as to be elastically deformable. Therefore, whether the front side connecting member and the rear side connecting member between the uppermost part and the lowermost part are rigid members or provided so as to be elastically deformable is arbitrarily determined in consideration of the number of steps of the entire lifting step, required rigidity, and the like. It may be decided.

  The present invention can be used for a wheel loader and can also be used for a work vehicle such as an off-road dump truck.

  DESCRIPTION OF SYMBOLS 1 ... Wheel loader (work vehicle), 2 ... Vehicle main body, 5B ... Rear wheel (wheel) 10, 10A ... Elevating step, 11 ... 1st front side connection member, 12 ... 1st rear side connection member, 13 ... 1st Step board, 14 ... 2nd front side connection member, 15 ... 2nd back side connection member, 16 ... 2nd step board, 17, 19, 22 ... Connection bracket, 17C, 19C, 19D, 22C ... Notch opening, 23 ... Laminated body, 23A ... an elastic plate, 27 ... a third front side connecting member, 28 ... a third rear side connecting member, 29 ... a third tread, DL ... a back separation angle defining line.

Claims (6)

A step is formed by a tread plate and a front connecting member and a rear connecting member whose lower ends are rotatably connected to both ends of the tread plate in the vehicle front-rear direction. Step,
The front connection member and the rear connection member of the step located at the top are pivotally connected to the lateral position of the vehicle main body, and are arranged in parallel at a predetermined interval in the vehicle front-rear direction.
The upper ends of the front connection member and the rear connection member of the step located below the step located at the uppermost part are rotatably connected to both ends in the vehicle front-rear direction of the step plate of the step located directly above,
The front side connecting member, the rear side connecting member, and the tread plate are rotatable about a connecting bolt penetrating in the vehicle width direction as a rotation axis.
Of the steps located above the step located at the bottom, at least the front connection member and the rear connection member of the step located at the top are rigid members,
Of the steps located below the step located at the top, at least the front connection member and the rear connection member of the step located at the bottom are provided so as to be elastically deformable. Lifting step. A first front connection member and a first rear connection member, the upper ends of which are rotatably connected to the side position of the vehicle body, and arranged in parallel at a predetermined interval in the vehicle front-rear direction;
A first tread plate rotatably connected between lower ends of the first front connecting member and the first rear connecting member;
A second front connection member and a second rear connection member, the upper ends of which are rotatably connected to both ends of the first tread plate in the vehicle front-rear direction;
A two-stage configuration including a second tread plate rotatably connected between lower ends of the second front connection member and the second rear connection member;
Each front-side connecting member, each rear-side connecting member, and each tread plate are rotatable about a connecting bolt that penetrates in the vehicle width direction as a rotation axis,
The first front connection member and the first rear connection member are rigid members,
The step of raising and lowering the work vehicle, wherein the second front side connecting member and the second rear side connecting member are provided so as to be elastically deformable. A first front connection member and a first rear connection member, the upper ends of which are rotatably connected to the side position of the vehicle body, and arranged in parallel at a predetermined interval in the vehicle front-rear direction;
A first tread plate rotatably connected between lower ends of the first front connecting member and the first rear connecting member;
A second front connection member and a second rear connection member, the upper ends of which are rotatably connected to both ends of the first tread plate in the vehicle front-rear direction;
A second tread plate rotatably connected between lower ends of the second front connection member and the second rear connection member;
A third front connection member and a third rear connection member, the upper ends of which are rotatably connected to both ends of the second tread plate in the vehicle front-rear direction;
A three-stage structure including a third tread plate rotatably connected between the lower ends of the third front connection member and the third rear connection member;
Each front-side connecting member, each rear-side connecting member, and each tread plate are rotatable about a connecting bolt that penetrates in the vehicle width direction as a rotation axis,
The first front connecting member, the first rear connecting member, the second front connecting member, and the second rear connecting member are rigid members,
The third front side connecting member and the third rear side connecting member are provided so as to be elastically deformable. In the raising and lowering step of the work vehicle according to any one of claims 1 to 3,
The elevating step of the work vehicle, characterized in that the elastically deformable front side connecting member and rear side connecting member include a laminated body of a plurality of elastic plates. In lifting step of the work vehicle according to any one of claims 1 to 4,
Upper ends and lower ends of all front side connection members and rear side connection members are rotatably connected to connection brackets fixed to the vehicle body or connection brackets provided at both ends in the vehicle longitudinal direction of all treads,
The connection bracket is provided with a notch opening that opens and accommodates a front connection member and a rear connection member that open and rotate toward at least one of the upper side and the lower side. . In the raising and lowering step of the work vehicle according to any one of claims 1 to 5,
A back separation angle defining line connecting a wheel provided on the vehicle main body and a vehicle rear lower portion of the vehicle main body, and a connection position of the front connection member and the rear connection member connected to the vehicle main body to the vehicle main body. A work vehicle lifting step characterized by being folded.

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